In processes for disposing of high borate content aqueous radioactive waste solutions or evaporator bottoms, such as generated in the operation of PWR nuclear power plants, it would be advantageous if the waste could be first cooled to near ambient temperatures. Preferred disposal methods, for example, utilize polymerization in situ methods for forming a leach resistant binder or solid matrix in which the radioactive waste is dispersed. Since such reactions are characteristically exothermic, excessive temperatures (100.degree. C.) can result which can pressurize the cured structure of the binder during the manufacture of the binder/waste matrix. A cooling step would thus be especially desirable.
Present solidification procedures, however, require the inapposite step of heating the waste to temperatures of between about 140.degree. F.-180.degree. F. and thus close to boiling water temperatutes prior to the onset of solidification procedures. Such a heating step is the currently practiced means by which precipitation is controlled effectively.
As a further aspect, the above-defined high borate content radioactive wastes are also highly susceptible to plugging and fouling of lines and vessels, such as the evaporation and heat exchange units, whenever a temperature control failure occurs in a part of the extensive circulation system through which such wastes are routed. Since resulting necessary repairs require exposure of workers to radiation hazards, advantages could be realized broadly if precipitation of solids in the waste solution could be satisfactorily solved by means other than controlling and maintaining critical operating temperatures at all points in the waste stream circulation system.